What...the... (E3D print head)

The other night I saved my printhead from runaway heating because I noticed smoke and discoloration in a small blob of pla -- I was in the process of troubleshooting thermistor contact with the heat block. I immediately shut off the printer, closed Repetier, disconnected the USB, then turned the printer back on so the active cooling fan could cool the head. No damage done, but that was a close call. When I inspected the head, I found that the capton tape had come loose and the thermistor was hanging in the breeze.